package collection;

//collection接口的演示

import java.util.ArrayList;
import java.util.Collection;

public class CollectionDemo {
    public static void main(String[] args) {
        Collection c=new ArrayList();
        c.add(new Point(1,2));
        c.add(new Point(3,4));
        c.add(new Point(5,6));
        c.add(new Point(7,8));
        c.add(new Point(9,0));
        c.add(new Point(1,2));
        System.out.println(c);//[(1,2), (3,4), (5,6), (7,8), (9,0), (1,2)]

        /*
            boolean contains(object o):
            判断当前集合是否包含给定元素o
            判断依据是给定元素是否与当前集合存在equals()比较为true的情况
         */
        Point p=new Point(1,2);
        boolean contains=c.contains(p);
        System.out.println("是否包含:"+contains);//重写之前为false,重写之后为true

        /*
            boolean remove(Object o):------一般不接收boolean的结果
            从当前集合中删除与给定元素o的equals（）比较为true的元素
            若存在重复元素只删除一次
         */
        c.remove(p);
        System.out.println(c);//[(3,4), (5,6), (7,8), (9,0), (1,2)]
        c.remove(p);
        System.out.println(c);//[(3,4), (5,6), (7,8), (9,0)]

        //集合中存放的是元素的引用
        Collection cc=new ArrayList();
        Point pp=new Point(1,2);
        cc.add(pp);//将pp添加到cc中------将pp的引用装到了cc中
        System.out.println("pp:"+pp);//(1,2)
        System.out.println("cc:"+cc);//[(1,2)]
        pp.setX(100);
        System.out.println("pp:"+pp);//(100,2)
        System.out.println("cc:"+cc);//(100,2)


        /*
        Collection c=new ArrayList();
        c.add("one");
        c.add("two");
        c.add("three");
        c.add("four");
        c.add("five");
        //集合重写了Object的toString（）方法，返回格式如下:
        //[元素1.toString(),元素2.toString(),元素3.toString(),...]
        System.out.println(c);//[one, two, three, four, five]
        System.out.println("size:"+c.size());//输出集合元素的个数
        //isEmpty()判断集合是否为空集（size()为0表示空集）
        System.out.println("是否为空集"+c.isEmpty());//false

        c.clear();//清空集合
        System.out.println("集合已清空");
        System.out.println(c);
        System.out.println("size:"+c.size());//0
        System.out.println("是否为空集:"+c.isEmpty());//true

         */
    }
}
